To help figure out how to create a flapping wing plane that will stand up to extreme wind and weather scientists are turning to nature for the answer.

Natural flyers like birds, bats and insects
outperform man-made aircraft in aerobatics and efficiency. University
of Michigan engineers are studying these animals as a step toward
designing flapping-wing planes with wingspans smaller than a deck of
playing cards.

A Blackbird jet flying nearly 2,000 miles per
hour covers 32 body lengths per second. But a common pigeon flying at
50 miles per hour covers 75.

The roll rate of the aerobatic
A-4 Skyhawk plane is about 720 degrees per second. The roll rate of a
barn swallow exceeds 5,000 degrees per second.

Select military
aircraft can withstand gravitational forces of 8-10 G. Many birds
routinely experience positive G-forces greater than 10 G and up to 14
G.

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"Natural flyers obviously have some highly varied
mechanical properties that we really have not incorporated in
engineering," said Wei Shyy, chair of the Aerospace Engineering
department and an author of the new book "The Aerodynamics of Low
Reynolds Number Flyers."

"They're not only lighter, but also
have much more adaptive structures as well as capabilities of
integrating aerodynamics with wing and body shapes, which change all
the time," Shyy said. "Natural flyers have outstanding capabilities to
remain airborne through wind gusts, rain, and snow." Shyy photographs
birds to help him understand their aerodynamics.

Pressure
generated during flight cause the flapping wings to deform, he
explained. In turn, the deformed wing tells the air that the wing shape
is different than it appears in still air. If appropriately handled,
this phenomenon can delay stall, enhance stability and increase thrust.

Flapping flight is inherently unsteady, but that's why it
works so well. Birds, bats and insects fly in a messy environment full
of gusts traveling at speeds similar to their own. Yet they can react
almost instantaneously and adapt with their flexible wings.

Shyy
and his colleagues have several grants from the Air Force totaling more
than $1 million a year to research small flapping wing aircraft. Such
aircraft would fly slower than their fixed wing counterparts, and more
importantly, they would be able to hover and possibly perch in order to
monitor the environment or a hostile area. Shyy's current focus is on
the aerodynamics of flexible wings related to micro air vehicles with
wingspans between 1 and 3 inches.

"These days, if you want to
design a flapping wing vehicle, you could build one with trial and
error, but in a controlled environment with no wind gusts," Shyy said.
"We are trying to figure out how to design a vehicle that can perform a
mission in an uncertain environment. When the wind blows, how do they
stay on course""

A dragonfly, Shyy says, has remarkable
resilience to wind, considering how light it is. The professor chalks
that up to its wing structure and flight control. But the details are
still questions.